I agree that the cold callers trying to sell something are only doing their job, but, although I’m not rude to them and do as minesaprosecco says, they are phoning me without my asking them to and usually at a most inconvenient time such as mealtimes! They are invading my home - why don’t they stand around in shopping malls, supermarkets etc?
On the other hand, the scammers are doing something completely different, they are trying to steal from vulnerable people and deserve all the time wasting and rudeness they get.
I had a new scam call yesterday. ‘Shirley’ (recorded message) called from my ISP provider to say that my ISP address had been compromised by several different countries but that they would provide a new ISP address and router. All I had to do was press 1 and speak to their technician. I hung up, then reported it to BT, my ISP provider. They asked if the caller had said they were from BT, and as they didn’t, they were unable to investigate. Oh well, I tried! 